L4.2 Wrist and Hands Flashcards
Carpal Bones (8)
*(Some Lovers Try Positions That They Cannot Handle)
- Proximal: Scaphoid, Lunate, Triquetrum, Pisiform
- Scaphoid + Lunate makes connection with radius
- Triquetrum + Pisiform has cartilaginous disc between ulna
- Distal: Trapezium, Trapezoid, Capitate, Hamate
Scaphoid
- Has proximal & distal pole → forms narrowing which blood supply runs (supplies distal half of scaphoid)
- Most frequently fractured of carpal bones
- Blood supply to proximal half compromised
Hamate
- Lig joins hamate & pisiform
- Deep to lig → ulna nerve
- Handlebar neuropathy (Ulna canal syndrome) → compression of ulna nerv
What is the palmar aponeurosis?
Palmar fascia: strong, skin attached tightly
What are the divisions of fascia of the hand?
- Fascia → flexor (ANT) & extensor (POS) retinaculum → continues to palm → forms palmar aponeurosis → Sends out extension of fascia: Separates palm into fascial compartments
- 5th metacarpal on the med side
- Hypothenar
- 3rd MC on the LAT side
- Thenar (Thumb side), further separates into:
- Superior Compartment
- Deep adductor compartment
- Thenar (Thumb side), further separates into:
- Central compartment in between Hypothenar and Thenar
- 5th metacarpal on the med side
What happens during the contracture of the palmar fascia?
- Contracture of palmer fascia: Dupuytrens Contracture
- Fascia may thicken/shrink → causes ring & little finger to flex
What is the flexor retinaculum (transverse carpal ligament) and its attachments?
- Roof of carpal tunnel
- Attach: 2 lat most (Scaphoid & Trapezium) & 2 med most carpal bones (Hamate & Pisiform)
What are the borders of the carpal tunnel?
And what causes carpal tunnel syndrome?
- Roof = Flexor retinaculum
- Floor = Carpal bones
- Prox bit identified by distal wrist crease.
- Repetitive action causes carpal tunnel syndrome
What are the structures running superficial and deep to the carpal tunnel?
-
Superficial to flexor retinaculum:
- PL tendon
- Ulna N & A
- Sup branch of radial A
- Palmar cutaneous branch of median N
-
Deep:
- FDS x4 tendons (3&4 superior; 2&5 deeper)
- FDP x4 tendons
- FPL tendon (Deep to median N)
- Median N
- FCR – enclosed by syno sheath
What is the extensor retinaculum?
- Attached to Radius, Triquetrum, Pisiform, FCU tendon (med)
- Action not as used ∴ less important
What are the boundaries of the anatomical snuff box?
And what are the structures through the anatomical snuff box?
- Boundaries:
- ANT: Tendon APL & EPB
- POS: EPL
- ROOF: Overly skin
- FLOOR: Scaphoid
- Radial N & A
1st layer of hand muscles (2 compartments, 2 mirrored muscles each)
- A) Thenar muscles (Origin: Flexor retinaculum; Insertion: Base of prox phalanges)
- Abductor pollicis brevis (AbdPB)
- Flexor pollicis brevis (FPB)
- B) Hypothenar (Origin: Flexor Retinaculum, Insert: Base of prox phalanges)
- Abductor digiti minimi (ADM)
- Flexor digiti minimi (FDM)
2nd layer of hand muscles (1 compartment, 4 muscles)
- Lumbricals (x4)
- From FDP tendons → pass LAT of digits → into extensor expansion (med 4 digits)
- Works on Flexor MC phalangeal joint & extension of interphalangeal joints
3rd layer of hand muscles (2 compartments, 3 muscles)
- A) Thenar
- Opponens pollicis (OP)
- Adductor pollicis (AddP) → 2 head (Inserts into phalanges)
- Oblique head → Origin: Flexor retinaculum
- Transverse head → Origin: Body of 3rd MC
- Both Insertion: Planlanx of thumb
- B) Hypothenar
- Oppenens digiti minimi (OPM)
4th layer of hand muscles (2 types, 7 muscles)
- Interossei
-
3 Palmer adductors (pAD)
- Origin: Shaft MC; Insertion: Prox phalange of the same digit (only 2,4,5)
- 3rd finger act as axis
-
4 Dorsal abductors (dAB)
- Origin: MC; Insertion: Prox phalange & extensor expansion
- Separate (Abduct) from midline
